<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>

<body>
    <div id="app">
        <p>
            {{a.a.a}}
            {{a.a.b}}
            {{a.a.c.a}}
        </p>
        <div>
            {{b}}
        </div>
    </div>
</body>
<script src="../js/mvvm.js"></script>
<script>
    var mvvm = new MVVM({
        el: '#app',
        data: {a:{a:{a:3,b:13,c:{a:1}}},b:'12'}
    })
</script>

</html>